1. Field of the Invention
The present invention is generally in the field of fabrication of microelectronic devices. More particularly, the invention is in the field of packaging microelectronic devices.
2. Background Art
Microelectronic devices, such as various types of semiconductor integrated circuits (ICs), micro-electro-mechanical systems (MEMS), nano-electro-mechanical systems (NEMS), radio frequency CMOS systems (RFCMOS), and micro-optical-electro-mechanical systems (MOEMS), are often separately packaged to protect the microelectronic devices from mechanical damage, chemical attack, light, extreme temperature cycles, electro-magnetic interference and other environmental effects.
Traditional packaging methods also provide mechanical support for the packaged device and facilitate handling of the device for subsequent attachment to a board or substrate. If desired, the package may also provide heat dissipation for the device. Although microelectronic packages may include a variety of forms to perform various functions, in general, the package includes a support to receive the device and encapsulating material to surround and protect the device from the surrounding environment.
Traditional methods of encapsulating such microelectronic devices are performed individually on each separate device, whereby the microelectronic device is mechanically adhered and electrically connected to a board or substrate. One commonly practiced method for such encapsulations is to adhesively attach the device to the pad of a leadframe, and forming electrical contacts between the device and the leads of the leadframe by wire bonding. The leadframe may then be mechanically attached and electrically coupled to the substrate by soldering the leads of the leadframe to the substrate.
Encapsulating methods and structures are generally configured to surround the microelectronic device, the wire bonds connecting the device to the leadframe, and a portion of the leadframe, leaving at least a portion of the leads exposed to the surrounding environment. The non-encapsulated lead portion is free to connect the packaged device to the board or substrate.
A drawback of employing traditional encapsulation processes such as those described above is that encapsulation is performed on each microelectronic device individually. Disadvantages include excessive time, labor, cost and scrap. Moreover, encapsulated microelectronic devices require separate packaging and assembly before they can be incorporated into a circuit, resulting in larger overall physical dimensions of such circuits.